The present invention relates generally to inkjet printheads, and more particularly to a wide-array inkjet printhead assembly.
A conventional inkjet printing system includes a printhead, an ink supply which supplies liquid ink to the printhead, and an electronic controller which controls the printhead. The printhead ejects ink drops through a plurality of orifices or nozzles and toward a print medium, such as a sheet of paper, so as to print onto the print medium. Typically, the orifices are arranged in one or more arrays such that properly sequenced ejection of ink from the orifices causes characters or other images to be printed upon the print medium as the printhead and the print medium are moved relative to each other.
In one arrangement, commonly referred to as a wide-array inkjet printing system, a plurality of individual printheads, also referred to as printhead dies, are mounted on a single carrier. As such, a number of nozzles and, therefore, an overall number of ink drops which can be ejected per second is increased. Since the overall number of drops which can be ejected per second is increased, printing speed can be increased with the wide-array inkjet printing system.
Mounting a plurality of printhead dies on a single carrier, however, requires a plurality of power, ground, and data lines for the printhead dies. As such, the single carrier must accommodate a plurality of electrical connections between the electronic controller and each of the printhead dies. In addition, a conventional inkjet printing system typically includes electrical interfaces in the form of conductive traces on a polyimide circuit. Since polyimides will absorb water, a conventional inkjet printing system which is subjected to a warm, humid environment is prone to trace corrosion. Furthermore, a leading cause of electrical shorts in a conventional inkjet printing system is interfacial separation caused by ink ingression at electrical interfaces of the polyimide circuit.
Accordingly, a need exists for routing power, ground, and data lines between an electronic controller and a plurality of printhead dies mounted on a single carrier. In addition, a need exists for eliminating electrical interfaces which are prone to corrosion and ink ingression.
One aspect of the present invention provides an inkjet printhead assembly. The inkjet printhead assembly includes a carrier and a plurality of printhead dies each mounted on a first face of the carrier. The carrier includes a plurality of conductive layers, a plurality of conductive vias, and a plurality of insulative layers, wherein the plurality of conductive layers include a first interface layer disposed on the first face of the carrier, a second interface layer disposed on a second face of the carrier, and at least one power layer, at least one data layer, and at least one ground layer each interposed between the first interface layer and the second interface layer. Each conductive via provides a conductive path through at least one of the insulative layers to provide electrical coupling between selected ones of the conductive layers, and each of the printhead dies are electrically coupled to the first interface layer.
In one embodiment, the carrier has a plurality of ink passages extending therethrough. As such, at least one of the ink passages communicates with the first face of the carrier and at least one of the printhead dies to provide ink to the printhead dies.
In one embodiment, each of the insulative layers is interposed between two of the conductive layers. In one embodiment, at least one of the insulative layers is interposed between the first interface layer and at least one of the at least one power layer, the at least one data layer, and the at least one ground layer. In one embodiment, at least one of the insulative layers is interposed between the second interface layer and at least one of the at least one power layer, the at least one data layer, and the at least one ground layer. In one embodiment, the at least one ground layer is interposed between the at least one data layer and the second interface layer.
In one embodiment, the at least one data layer includes at least one print data layer and at least one non-print data layer. In one embodiment, the at least one ground layer is interposed between the at least one non-print data layer and the second interface layer. In one embodiment, the at least one ground layer is interposed between the at least one print data layer and the at least one non-print data layer. In one embodiment, the at least one power layer and the at least one ground layer are disposed in one plane. In one embodiment, the at least one data layer carries at least one of print data and non-print data.
In one embodiment, the second face of the carrier is opposed to the first face of the carrier. In one embodiment, at least one of the insulative layers comprises a ceramic material.
Another aspect of the present invention provides a method of forming an inkjet printhead assembly. The method includes providing a plurality of conductive layers including a first interface layer, a second interface layer, at least one power layer, at least one data layer, and at least one ground layer, providing a plurality of insulative layers, and providing a plurality of conductive paths through at least one of the insulative layers to provide electrical coupling between selected ones of the conductive layers. As such, the method includes disposing the first interface layer on a first side of a first of the insulative layers and disposing the second interface layer on a second side of a second of the insulative layers, and interposing the at least one power layer, the at least one data layer, and the at least one ground layer between the first of the interface layers and the second of the interface layers. The method also includes mounting a plurality of printhead dies on and electrically coupling the printhead dies to the first interface layer.
Another aspect of the present invention provides a carrier adapted to receive a plurality of printhead dies. The carrier includes a first interface adapted for electrical communication with the printhead dies, at least one power layer for conducting power, at least one data layer for carrying data, a second interface, a plurality of insulative layers, and a plurality of conductive vias. The insulative layers include at least one insulative layer interposed between the at least one power layer and the at least one data layer. Each of the conductive vias provide a conductive path through at least one of the insulative layers to provide electrical coupling between selected ones of the first interface, the at least one power layer, the at least one data layer, and the second interface.
Another aspect of the present invention provides a method of forming a carrier for a plurality of printhead dies. The method includes providing a first interface adapted for electrical communication with the printhead dies, providing at least one power layer for conducting power, providing at least one data layer for carrying data, providing a second interface, interposing at least one insulative layer between the at least one power layer and the at least one data layer, and providing a conductive path through the at least one insulative layer to provide electrical coupling between selected ones of the first interface, the at least one power layer, the at least one data layer, and the second interface.
The present invention provides a three-dimensional, internal electrical routing scheme which facilitates the routing of power, ground, and data lines between an electronic controller and a plurality of printhead dies each mounted on a single carrier.